Jacobi's four-square theorem

Lagrange's four-square theorem - Wikipedia

Seatings and Sums of Squares

Math & Physics - Lagrange's Four-square Theorem Follow instagram.com/ins.map.lb

Solved In Number Theory, Lagrange's four-square theorem

Lagrange's four-square theorem - Wikiwand

Discrete quantum computation and Lagrange's four-square theorem

Pythagorean Theorem

Why was this visual proof missed for 400 years? (Fermat's two square theorem)

Proving the Pythagorean Theorem. Some algebraic and geometric proofs of…, by Michele Diodati, Not Zero

MathType - Lagrange's four-square theorem states that every natural number can be represented as the sum of four integer squares. Proved by Joseph Louis #Lagrange in 1770, it can be regarded as